The art of milling or comminuting grain by rotary grinding and/or cutting or chopping devices is extremely old and well developed. Conventionally, such mills have been ponderous and slow in operation. There is a need for a small, efficient grain grinder for making whole wheat flour and the like rapidly, grinding it very shortly or immediately before flour is to be used so as to void loss of vitamins and other nutrients in the whole grain. Such devices are finding favor in homes because they make it possible to have freshly ground whole grain flour on demand, which can be made into bread and other products while the flour retains the nutrients which are too often removed in conventional milling or lost in prolonging storage in warehouses and stores.
In U.S. Pat. No. 3,880,367 there is disclosed a portable mill for grinding wheat and other grains comprising two annular grinding stones, one fixed and the other driven, each secured to steel cutting burrs which have their cutting edges substantially in the grinding plane and of which receives grain through a central opening in the burrs. The grain is cut or chopped by secant or non-radial cutter elements closely facing each other and set for shearing action. These force the grain as it is cut radially outward between annular grinding stones which are secured respectively to the stationary and the driven rotary burr. The driven burr is directly connected to the drive shaft of the motor, the motor being provided with a thrust bearing to oppose the thrust between the chopping and grinding elements. A hopper above the stones supplies the feed and includes a removable botton sealed to the sides, and is provided with a metering opening to feed grain at controlled rate into a feed channel connected with the inlet through the stationary burr. The spacing between the two grinding stones is adjusted by moving the mounting block on which the fixed stone is secured.
In U.S. Pat. No. 3,688,996 there is disclosed a flour mill comprising an upstanding box-like housing including a substantially cylindrical abrasive grinding wheel having a multiplicity of spirally disposed tooth-like breaks suitably fastened to one of the sidewalls of the housing, a substantially similar grinding wheel opposingly mounted and journaled for rotation in the sidewall opposite the fixed grinding wheel, and means for driving the rotating grinding wheel. The fixed grinding wheel is provided with an entranceway in one of its walls, a downwardly sloping hopper-like bottom portion is supported by the fixed wheel in the housing and includes an exitway coincident with the entranceway of the fixed wheel. The wheels are selectively spaced apart with respect to each other to grind grain into flour or cereals. The fixed wheel is mounted on a mounting block which has a resilient portion for adjusting the spacing between the respective wheels.
Other examples of portable type flour grinding mills may be found in U.S. Pats. Nos. 585,536; 755,989; 1,033,878; 1,435,130; 2,284,789; and 3,688,996.
It is an object of the present invention to provide a flour mill of simple construction including means operable to control and contain flour and grain within the mill.
A further object of this invention is to provide means for selectively positioning the grinding wheels with respect to each other for grinding flour or cereal.
It is another object of this invention to provide a portable flour mill which can be used effectively to grind a wide variety of grains.
It is still another object of this invention to provide a portable flour mill that can be easily cleaned and/or dissassembled.
It is yet still another object of this invention to provide a new and improved design for the grinding wheels of a portable flour mill.
The present invention will be more fully appreciated upon reference to a detailed description of a presently preferred embodiment thereof.
Generally, the present invention comprises an upstanding box-like housing including a substantially cylindrical abrasive grinding wheel having both flat & tapered areas on its grinding face, suitably fastened to a removable interior wall, a substantially cylindrical abrasive grinding wheel having five symmetrically disposed "v" shaped radial grooves on its grinding face opposingly mounted and jounaled for rotation in an interior wall opposite the fixed grinding wheel, and means for driving the rotating grinding wheel. The fixed grinding wheel is provided with an entranceway in one of its walls. The grinding face of each grinding wheel has a flat outer portion and a concave inner portion. A downwardly sloping feed hopper rests on a plate fixed to the removable interior wall and includes an exit-way coincident with the entranceway of the fixed wheel. The wheels are selectively spaced apart with respect to each other to grind into flour or cereals. Means for adjusting the spacing between the respective wheels by moving the movable wheel is provided in the apparatus here disclosed.
The entranceway aforesaid leads from a loading chamber for the grain or cereal into the grinding area of the mill. Preferably the entry through the fixed stone comprises a circular opening or aperture, the midpoint of which is coincident with the midpoint of the grinding face of the stone.